1. Field of the Invention
This invention relates to the general fields of coatings and building materials, and more particularly to wall and ceiling coverings with a sprayed on acoustical type pattern for use in mobile homes, conventional homes, recreational vehicles, and the like, and a method of manufacturing of such coatings and materials.
2. Prior Art
Through the years, manufacturers of mobile homes have tried to develop construction methods and materials which would give the mobile home the "feel" and appearance of an "on site built home", and which would be able to withstand the physical stresses and distortions of moving the home from one location to another. Duplication of floor areas and windows is generally not difficult, as most "on site" floor coverings are directly usable, and window glass can be removed for transport, if necessary. However, the walls and ceiling of mobile homes typically have grooves or moldings where the material used to form the walls or ceiling is joined, markedly distinguishable from an on site built home.
Many on site built homes have seamless ceilings and walls which have a pattern on them. One such pattern is provided by a sprayed on ceiling, giving a pebbled appearance with a material resembling plaster and referred to as a "sprayed on acoustical pattern." Many attempts to produce this sprayed on acoustical pattern in mobile homes have been made without success. When a sprayed on acoustical ceiling of plaster is applied in a mobile home, the desired seamless appearance is produced, but when the mobile home is moved, the ceiling often cracks, necessitating the repair or replacement of the ceiling after each move.
Some manufacturers of modular homes (a home moved only once on a flatbed truck) have used a liquid plastic film material containing plastic chips to obtain a flexible seamless wall and ceiling covering. Because this system requires very expensive special preparation of the surface over which it is to be applied, and considerable skill for its installation, it is not well suited for the mobile home industry. Another disadvantage is that the ceiling produced is not sufficiently resistant to the stresses which are inherent in moving a mobile home from place to place. Thus, cracks and seams will appear after a move which detract from the appearance of the walls and ceiling.
Another prior art covering consists of a thin plastic film coated on one side with adhesive. The exposed side of the film has an appearance which approximates a shot acoustical ceiling. The covering is supplied in twelve foot wide continuous rolls which enables a seamless appearance to be achieved. The film, however, lacks any appreciable "self-leveling" capacity, and requires extensive preparation of the wall or ceiling prior to its application. (A film is self-leveling when the surface of the film bonded to the wall or ceiling is able to locally deform sufficiently to prevent any irregularities from appearing on the opposite exposed surface.) All irregularities in the wall or ceiling, e.g., seams, cracks, etc., have to be puttied, taped, and sanded to provide a smooth surface, as any flaw in the covered surface "telegraphs through" the film because of the small thickness of the film. Thus, each ceiling panel to be covered must be perfectly level with the adjacent panel, and each panel must be free of surface irregularities. Another major disadvantage of this material is that it cannot be repaired without the repair being readily detectable.
One prior art material provides the desired appearance, and because it utilizes a urethane foam backing material of significant thickness, is self-leveling. This material is manufactured by applying resin coating onto a sea sponge type urethane substrate, drying the coated substrate thus formed, and thereafter crushing the dried substrate to form a composite textured material. While the product so formed is highly suited for the intended use, the process by which it is formed, especially the crushing of the material to obtain the texture, is highly sensitive to various parameters which can be difficult to control.
Other methods of providing textured coatings are known in the prior art, such methods including the use of expandable polystyrene beads as is disclosed in U.S. Pat. No. 2,862,834. Other patents describing the fabrication of products having textured surfaces include U.S. Pat. Nos. 2,827,727; 3,502,539; 3,607,341; 3,615,972; 3,639,160; 3,649,324; 3,752,695; 3,755,518; 3,908,059 and 3,919,451. However none of these methods or products seem to have found their way into the construction industry, particularly the mobile and modular homes industry, in any substantial commercial quantities, and it is to this specific purpose to which the preferred embodiment of the present invention is directed.